1. Field of the Invention
The present invention relates to a method and apparatus for forming a flexible mat of concrete panels for placement on surface areas at which surface erosion can occur. The mat is defined by a plurality of side-by-side, spaced, interconnected concrete panels. More particularly, the present invention relates to a method and apparatus for continuously forming as a unit a flexible mat defined by a plurality of interconnected concrete panels including flexible interconnections that extend between adjacent panels, for providing pre-formed mats that can serve as walkways or roadways, and that can also serve to provide erosion control along drainage ditches and water channels, and around the banks of bodies of water.
2. Description of the Related Art
The shorelines and banks of lakes, ponds, rivers, and streams often undergo undesirable erosion. Because of the effects of rapidly flowing water or because of periodic changes in water levels, a washing effect results along the shorelines and banks, and that washing effect gradually erodes the surfaces that are contacted by the moving water. Similarly, drainage ditches and drainage channels for carrying away excess surface water also experience considerable undesirable erosion, particularly during and immediately after times of heavy rainfall.
In the past, erosion caused by moving water was attempted to be controlled by placing stones of various sizes along the banks of waterways or within drainage ditches and channels. Such stones, sometimes referred to as rip-rap, were dumped or otherwise irregularly placed in the path of the water movement in an effort to reduce the velocity of the moving water, and thereby minimize the washing-away effect of the water, to prevent the receding of the shorelines of the bodies of water and to reduce the deepening of drainage ditches and channels. However, that attempted solution to the erosion problem was often only a short-term solution, which over time became less and less effective. Because the moving water undermined the earth below the stones by washing away part of the underlying earth, the stones ultimately sank into the earth and became submerged into the resulting silt, thereby becoming ineffective to control erosion over a long period of time.
Various proposals have been made to attempt to solve the erosion problem by a method other than the mere dumping of stones in the water flow path. Some proposals involved erosion control mats formed from interconnected concrete panels of one shape or another. Some of those proposed mats were formed from concrete blocks that included internal passageways within the blocks through which cables or ropes could be threaded to interconnect the concrete blocks in a desired array. Sometimes the blocks were in contact with each other or were in interlocked form. Other proposals included embedding connecting elements within the concrete blocks to avoid the need to provide passageways for cables or ropes, and to avoid the separate step of interconnecting the blocks. However, the proposed structures were difficult to manufacture quickly and economically at a job site, and consequently they were not widely utilized.
In addition to control of erosion caused by moving water, mats formed from side-by-side, interconnected concrete panels can also be utilized to provide walkways, roadways, and parking areas, to control usage-based erosion of the ground in off-road or restricted-usage applications. Additionally, such mats based upon interconnected concrete panels can also be useful to provide more permanent road berms or shoulders, to replace the usual gravel-based berms or shoulders that gradually become eroded and rutted by vehicles wandering off the road. Again, however, pre-formed mats for walkway, roadway, parking, and road berm purposes have heretofore been too costly to produce, In comparison with other alternatives.
The present invention is intended to provide an improved method and apparatus for forming flexible mats made from spaced concrete panels, so that the mats can be quickly and economically produced at or near a job site, to avoid the need to transport the mats over long distances.
Briefly stated, in accordance with one aspect of the present invention, apparatus is provided for continuously forming a flexible mat that is defined by a plurality of spaced, interconnected concrete panels. The apparatus includes a rotatable drum having a plurality of circumferentially-disposed mold cavities carried at an outer periphery of the drum. A trough overlies the drum and has an elongated outlet opening extending across an axial direction of the drum for providing a substantially uniform flow of a flowable concrete mix into the respective mold cavities as the mold cavities pass beneath the outlet opening. A first support is provided adjacent to the drum for rotatably receiving a roll of open mesh material in web form for feeding the mesh material into contacting engagement with the periphery of the drum and in the drum rotation direction before the trough. A second support is provided adjacent to the drum and behind the trough in the drum rotation direction for rotatably, receiving a roll of a base material in web form for feeding the base material into contacting engagement with the periphery of the drum.
In accordance with another aspect of the present invention, a method is provided for continuously forming a flexible mat defined by a plurality of spaced, interconnected concrete panels. The method includes providing a rotatable drum having a plurality of circumferentially-disposed, peripheral mold cavities. A plurality of longitudinally-extending connector elements and a plurality of transversely-extending connector elements are fed into contacting engagement with the periphery of the drum and in overlying relationship with the mold cavities. The drum is rotated and a flowable concrete mix is deposited into successive mold cavities as the drum rotates to substantially fill the mold cavities to form concrete panels. As the drum is rotating, a web of base material is brought into contacting engagement with the periphery of the drum to overlie and cover the filled mold cavities to prevent concrete mix from falling from the mold cavities as the drum is rotating. The drum is further rotated, and the concrete panels are released from the mold cavities by gravity and are in overlying contact with the web of base material to form a continuous mat having concrete panels that bond to the base material upon curing of the concrete mix, wherein the resulting mat has a predetermined length and width.